LAUSR

Very recently, compound heterozygous loss‐of‐function mutations in TELO2 were shown to underlie the newly‐described You‐Hoover‐Fong syndrome. TELO2 forms part of the co‐chaperone triple T complex (TTT complex), which plays an important role in the maturation and stabilization of the phosphatidylinositol 3‐kinase‐related protein kinases (PIKKs). Patients with mutations in TELO2 present with microcephaly and associated intellectual disability, postnatal growth retardation and dysmorphic features. Here, we describe Danish sisters with two novel mutations in TELO2. In particular, we highlight the clinical features of the 22‐year index patient, which are more severe than the original patients described, thereby expanding the clinical spectrum of YHFS.